Numerous medical conditions are caused by insufficient blood flow to certain tissues. For example, angina and myocardial infarction are caused by insufficient blood flow to cardiac muscle, and ischemic stroke is caused by insufficient blood flow to the brain.
US Patent Application Publication 2002/0103413 to Bugge et al., which is incorporated herein by reference, describes an implanted device for utilizing at least a part of the hydraulic energy generated by the heart to power various apparatus. The device typically includes a hydraulic motor powered by pressurized blood, which converts hydraulic energy into mechanical or electrical energy. The device typically stores the energy, and uses the stored energy to power an executing device, such as a pump or an electric motor. For some applications, the hydraulic motor is connected directly to one or more ventricles of the heart. Numerous embodiments of the device are described.
U.S. Pat. No. 4,527,549 to Gabbay, which is incorporated herein by reference, describes techniques for providing improved cardiac assist by the use of a intraaortic balloon. A single small balloon is placed in the ascending aorta close to the aortic valve, such placement being described as effective for producing a substantially stronger augmentation of heart action than with the use of a longer balloon normally placed, for example, in the descending aorta. Multiple small balloons positioned in the aortic arch, with or without a large balloon in the descending aorta, can be used to provide even stronger coronary flows.
U.S. Pat. No. 6,730,118 to Spenser et al., which is incorporated herein by reference, describes a valve prosthesis device suitable for implantation in body ducts. The device comprises a support stent, comprised of a deployable construction adapted to be initially crimped in a narrow configuration suitable for catheterization through the body duct to a target location and adapted to be deployed by exerting substantially radial forces from within by means of a deployment device to a deployed state in the target location, and a valve assembly comprising a flexible conduit having an inlet end and an outlet, made of pliant material attached to the support beams providing collapsible slack portions of the conduit at the outlet. The support stent is provided with a plurality of longitudinally rigid support beams of fixed length. When flow is allowed to pass through the valve prosthesis device from the inlet to the outlet, the valve assembly is kept in an open position, whereas a reverse flow is prevented as the collapsible slack portions of the valve assembly collapse inwardly providing blockage to the reverse flow.